Web conveying apparatus



Nov. 1, 1966 F. E. BAUER ETAL 3,282,488

WEB CONVEYING APPARATUS Filed Feb. 4, 1965 v 2 Sheets-Sheet 1 A 3 3 A 3 A @awwa INVENTORS. FRITZ E. BAUER THOMAS BEALL Nov. 1, 1966 F. E. BAUER ETAL WEB CONVEYING APPARATUS 2 Sheets-Sheet Filed Feb. 4, 1965 m h w m w NMM W r W 7 W mw fi mm B 5 0 2 M m. .b 4d I! L n l United States Patent 3,282,488 WEB CONVEYTNG APPARATUS Fritz E. Bauer and Thomas Beall, North Adams, Mass., assignors to Crornpton & Knowles Corporation, Worcester, Mass., a corporation of Massachusetts Filed Feb. 4, 1965, Ser. No. 430,391 4 Claims. (Cl. 226-195) This invention relates to web conveying apparatus of the type having a dancer roll for maintaining tension in the travelling web.

The dancer roll commonly used in web conveying apparatus is a heavy roll mounted in a set of vertical guides so as to be freely movable up or down while rotating about its longitudinal axis. It is mounted so that a loop of the travelling web acts as a support for the roll, whereby the .roll maintains the web under tension by pulling the loop downwards through the force of gravity.

A problem encountered in the use of dancer rolls is that when the web breaks, the roll will suddenly drop freely, damaging the roll or the machine frame.

The apparatus of the present invention provides an overrunning clutch assembly geared to the dancer roll and so arranged as to power the vertical descent of the roll and thus limit its descent speed. The roll is free to move upward without restraint, since the clutch is designed to disengage during ascent of the dancer roll.

The invention will be explained in further detail below in reference to the accompanying drawings, in which:

FIG. 1 is a side elevational view, partly in section, of a web conveying apparatus embodying the invention;

FIG. 2 is a sectional View on the line 22 in FIG. 1; and

FIG. 3 is a sectional view on line 33 in FIG. 1.

Referring to FIG. 1, a web 1 of fibrous material is transported through suitable treating apparatus (not shown) by a conveying system comprising a series of lower driven rolls 2 and upper idle rolls 3. The lower rolls 2 are driven by motors 13 through belt drives 14 passing around sprockets 22. The web 1 passes under the first driven roll 2, thence over the first idler roll 3, thence under the second driven roll 2, and so on to a dancer roll 4 suspended in vertical guides (not shown) which prevent horizontal movement of the dancer roll. The web extending downward from the third idler roll 3 passes under the dancer roll 4, then upward and over the fourth idler roll 3, and so on around the remaining driven and idler rolls.

Each end of dancer roll 4 is provided with a trunnion 4a rotatably mounted in a bearing 6 forming part of an adjacent bearing housing 5, the two plate being movable vertically in the aforementioned guides (not shown). A chain 7 has its opposite ends connected to the upper and lower edges, respectively, of each housing 5 and passes around corresponding sprockets 8 and 9. The two upper sprocket 8 and the two lower sprockets 9 (only one of each being shown) are mounted on the opposite end portions of upper and lower transverse shafts 8a and 9a, respectively, suitably journaled in stationary bearings (not shown). At one of its end portions, lower shaft 9a carries a sprocket 18 (FIGS. 2 and 3) which is driven by chain 19 from sprocket on one end of shaft 11. Also mounted on shaft 11 is an overrunning clutch 10, which may be of the same type as that shown in Patent No. 2,981,118 entitled Step by- Step Feed Mechanism issued April 25, 1961.

This type Patented Nov. 1 1 966 of clutch is manufactured by Formsprag Co. of Van Dyke, Michigan. The output side of clutch 10 is keyed to shaft 11. A sprocket 21 loosely mounted on shaft 11 is connected to the input side of clutch 10 and is driven by chain 16 from sprocket 24 mounted on shaft 25. Fixed to shaft 25 is a gear 23 meshing with gear 12 mounted on shaft 15 which forms an extension of one of the driven rolls 2.

In operation, sprocket 21 is continuously driven clockwise (as viewed from the left in FIG. 3) at constant speed from one of the driven rolls 2 through the driving connection including gears 12 and 23 and chain 16. Through the connection including chain 7, sprockets 8, 9, 18 and 20 and chain 16, shaft 11 is driven counterclockwise (as viewed from the left in FIG. 3) as dancer roll 4 ascends and is driven in the opposite direction as the dancer roll descends. The clutch 10 is adapted to engage and therefore couple sprocket 21 to shaft 11 only when the latter rotates clockwise relative to sprocket 21 (as viewed from'the left in FIG. 3). In other words, the clutch 10 will overrun at all times except when dancer .roll 4 descends at sufficient speed to cause such clockwise rotation of shaft 11 at a speed tending to exceed the constant speed of the clockwise rotation of sprocket 21. When this exceptional condition occurs, as due to breakage of web 1 with resultant free falling of dancer roll 4, clutch '10 becomes engaged in the well-known manner so as to couple to sprocket 21 to shaft 11, where- 'by the speed of the dancer roll descent is limited by the constant rotational speed of sprocket 21. Thus, with suitable selection of the relative diameters of gears Hand 23 and sprockets 24 and 21 (which determine the constant speed at whch sprocket 21 rotates), descent of the dancer roll 4 at an excessive or damaging speed is prevented by the braking action which the constant speed sprocket 21 exerts on this roll through clutch 10 and the connection 7-9, 18-20 and 11.

We claim:

1. Web conveying apparatus comprising a plurality of rotary transport rolls disposed for engagement of their peripheries with a web to be transported, substantially constant speed driving means operatively connected to at least one of said rolls for rotating the same to pull the web along a'path in engagement with said peripheries, a dancer roll movable vertically in position to be supported by a loop of the web in said path, a first rotary element operatively connected to said driving means and rotatable thereby in one direction at substantially constant speed, a second rotary element, an operative con nection between the dancer roll and aid second element for rotating the second element at a speed proportional to the speed of vertical movement of the dancer roll and in a direction determined by the direction of said vertical movement, said connection being operable to rotate the second element in the same direction as the rotation of said first element as the dancer roll descends, and an overrunning clutch interposed between said rotary elements and operable to interconnect them in response to rotation of the second element in said same direction at a speed greater than the rotational speed of the first element, whereby said driving means are operable to brake the descent of the dancer roll.

2. Apparatus according to claim 1, in which said first rotary element is connected to the driving means through one of said transport rolls.

3. Apparatus according to claim 1, comprising also vertically movable bearing housing means mounting the dancer roll for rotation, said Operative connection in- References Cited by the Examiner gllding a chain havinkg tends integconrtlliictecll1 through 1soak; v v UNITED sTATES PATENTS using means, sproc e s suppor ng e c am 1n a o a and adapted to be driven through the chain by vertical 1946264 2/1934 Baer 226 195 X movements of the dancer roll, and a driving connect-ion 5 2'606493 8/1952 Hasiaert' between one of said sprockets and said second rotary 2934338 4/1960 Labmve 242 75'3 element 2,981,118 4/1961 Mornll 19241 X 4. Apparatus according to claim 1, in which said secand rotary element is a shaft on which said first rotary HENSON D, JR., Przmary Examiner. element is loosely mounted. 10 J. N. ERLICH, Assistant Examiner. 

1. WEB CONVEYING APPARATUS COMPRISING A PLURALITY OF ROTARY TRANSPORT ROLLS DISPOSED FOR ENGAGEMENT OF THEIR PERIPHERIES WITH A WEB TO BE TRANSPORTED, SUBSTANTIALLY CONSTANT SPEED DRIVING MEANS OPERATIVELY CONNECTED TO AT LEAST ONE OF SAID ROLLS FOR ROTATING THE SAME TO PULL THE WEB ALONG A PATH IN ENGAGEMENT WITH SAID PERIPHERIES, A DANCER ROLL MOVABLE VERTICALLY IN POSITION TO BE SUPPORTED BY A LOOP OF THE WEB IN SAID PATH, A FIRST ROTARY ELEMENT OPERATIVELY CONNECTED TO SAID DRIVING MEANS AND ROTATABLE THEREBY IN ONE DIRECTION AT SUBSTANTIALLY CONSTAT SPEED, A SECOND ROTARY ELEMENT, AN OPERATIVE CONNECTION BETWEEN THE DANCER ROLL AND SAID SECOND ELEMENT FOR ROTATING THE SECOND ELEMENT AT A SPEED PROPORTIONAL 